Cellular Network Infrastructure

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Normally, all user plane data in UMTS networks are sent in point-to-point channels from the network to the user. Those are called "dedicated" radio channels which exist between the network and one given phone/subscriber at a time.

Service Area Broadcast is an exception to that rule. It permits user data (so-called SMS-CB data) to be broadcast by the network in a way that can be received by all phones in the coverage area of the given Service Area (group of cells) simultaneously.

Currently it is not yet supported by any of the Osmocom components. We would love to implement it, but somebody would have to contribute related code and/or funding.

Assuming that the NodeB+RNC connected to OsmoMSC or the hNodeB connected to OsmoHNBGW implement SABP, all we'd need to do is to implement a kind of SABP multiplexor inside OsmoHNBGW so that the CBC has to talk only once to the HNBGW, which then takes care of distributing that information to all hNodeB in the service area.

We would also want to implement a simplistic CBC which implements SABP on Iu-BC towards the RNC/HNBGW, as well as 3GPP TS 48.049 for GSM. This way one could easily configure certain CBS / SMS-CB messages on the CBC, and the CBC would distribute it to all BSCs/RNCs/HNBGWs in the respective service area, who in turn communicate the messages to the MSs.